As I early wrote in an article how to migrate ESB services to OSB service, Oracle has written an whitepaper on how to run AIA in combination with OSB.
This article describes the approach to be taken if you must used the OSB as service bus in an AIA environment.
Technical it is possible to move the ESB service to OSB, based on AIA. But their are some restrictions or pitfalls to take inton using AIA on OSB.
The stylesheets in AIA are relative complex, I am not an XSLT guru, but sometimes it is hard to read/interpret the XSLT. They could work in OSB, but you do not have a nice diagrammer as in JDeveloper. You must use the Eclipse source editor.
In Oracle SOA Suite and with AIA on top of it, Oracle has added some extended functions to the XSLT/XPATH functionality. These functions are available in BPEL/ESB, but when you use OSB, these functions are not available. You must add this functions, via a JAR file to the OSB classpath, but then you must make sure these functions work on OSB. OSB is running on Java 1.6, while Oracle SOA Suite + AIA is running on Java 1.5
The AIA XSD schema's are installed in the AIA installation directory of the Oracle Application Server. If you use OSB, you should take care to copy the XSD/WSDL definitions to the OSB environment. You have to maintain two XSD/WSDL directory trees or, if possible, make a reference to the central AIA directory.
Creating your own OSB services, instead of using the ESB ones, has impact on support of the AIA stack. IMHO you do not have AIA support on your own developed services, you can fall back on the normal Oracle OSB support.
The link to the Oracle AIA/OSB white paper:
Oracle AIA with OSB will be available/planned in SOA 11gR2.